Controlling medical costs seems about as possible as using a sink drain stopper to plug Niagara Falls.

The industry has too many moving parts. Advanced medical imaging — especially computed tomography, known as CT, and magnetic resonance imaging, or MRI — is becoming highly visible, and the U.S. Government Accountability Office is noticing.

A recent GAO study reported that the use of advanced medical imaging by doctors and doctor groups that own or lease imaging equipment — as opposed to doctors who refer patients to hospitals and clinics — is widening.

When doctors have imaging done in their offices, it's called self-referring. The volume of self-referred imaging is rising dramatically.

GAO is telling Congress this:

“Self-referring providers (mainly doctors) referred about two times as many of these services as providers who did not self-refer,” or who referred patients to independent imaging clinics or hospitals, the report states. “Financial incentives for self-referring providers were likely a major factor driving the increase in referrals.

“GAO estimates that in 2010, providers who self-referred likely made 400,000 more referrals for advanced imaging services than they would have if they were not self-referring. These additional referrals cost Medicare about $109 million. ... Medicare Part B expenditures — which include payments for advanced imaging services — are expected to continue growing at an unsustainable rate,” the report added.

The $109 million is just the effect from Medicare patients. It might be much higher for the general population.

What's going on?

Brian Ball, national vice president of health cost solutions in Chicago for New York-based USI Insurance Services, says MRI and CT imaging once was the domain of hospitals, which needed them for trauma and emergency cases.

But in recent years, doctors realized they could send revenue to themselves if they operated their own equipment. So the idea spread, said Ball, who spoke recently in San Antonio about employer health benefit cost trends at a BBVA Compass seminar.

Doctors have to cover the cost of buying such imagining machines, which might be a factor in the explosion in volume of imaging procedures.

Ball, however, listed positive results of this boom. It's more convenient for patients to walk down the hall in their doctors' offices for imaging than going to a separate location. Imaging results can be read and relayed to patients more quickly. Doctors can justify more imaging as preventative medicine, too, and it could reduce malpractice accusations.

“Some of it is logical,” Ball said.

But costs for the same services illogically vary. The same $700 imaging service at a clinic might be $1,700 from a hospital, Ball said.

One problem is the difference between Medicare and private insurance companies. Private insurers can control utilization of imaging services through prior-authorization requirements. Medicare, on the other hand, does not manage costs at the front end but is more efficient at processing and paying claims than private insurers, Ball said.

With cross-currents of processes and differences between who pays how much for what and when, costs leak out of control.

“Unsustainable” is the word the GAO used. Sounds like an accurate diagnosis for medical industry cost trends.